u/Aware-Butterfly8688

In case you're still confused, this is a One Piece prompt.

Disclaimer: This may not be the most accurate explanation of nonbinary gender identity, so I'm sorry if I got anything wrong.

First of all, all three humans (Frisk, Chara, and Kris) are nonbinary. That part is not up for debate. However, I think a lot of us are ignoring what nonbinary really means. So many people are treating that label as if it's just a third gender. I think it would be as meaningful to say "Frisk can't be a girl, because they have hanging ear lobes!" In defense of the people who fight tooth and nail for their headcanon of Female Frisk or Male Kris, femininity, masculinity, and nonbinary aren't mutually exclusive. Nonbinary isn't just a third gender.

Now obviously, there is still an issue with where a lot of people take these kinds of headcanons. See, the specific terminology for the humans' gender identity isn't what's important here. What matters is the pronouns. All three humans have they/them pronouns. I mean, there's some debate as to whether Chara is meant to represent the player, since Chara is the one you name at the start of the game, but the in-game dialogue refers to Chara as "they" so for here I am going to see Chara as nonbinary just like Frisk and Kris.

Frisk could be a fem-presenting nonbinary kid, Kris could be a masc-presenting binary teen. However you think these characters would present, I don't think would be contradicted by the games. There's no instance where Frisk or Kris refuses to wear certain clothes like the tutu or the princess gloves. Kris is even willing to wear that sparkly blue dress, even though it's stuck to the mannequin. So I do think it's still respecting the canon to imagine one of the characters as a nonbinary boy, a nonbinary girl, a mix of the two, agender, or gender fluid. Or something else entirely. Maybe Frisk would like being called a girl! We dont have enough information to disprove it! That part is up for interpretation. What's not up for interpretation is the fact that the KFC gang are not cis, and they all use they/them pronouns.

There's an analogy for pronouns I heard from a YouTuber that I really like. It's like the McDonald's toys. It's not very helpful to refer to the Happy Meal toys as "the girl's toy" and "the boy's toy." If McDonald's is offering a Barbie toy or a GI Joe toy, you shouldn't have to say the gender that the toy is "meant for" when telling the cashier what you want. Just say that you want the Barbie toy, or that you want the GI Joe toy. GI Joe isn't just a girl's toy or just a boy's toy, it's a GI Joe toy. That's the descriptor that matters. Is Frisk a boy? A girl? You can write down your theories about the specifics of what Frisk identifies as until the cows come home. But the label that comes first is their pronouns. Their they/them pronouns.

TL;DR: Being nonbinary is a spectrum and it's not very helpful to say "Frisk can't be a girl, they're nonbinary" instead of explaining how Frisk's gender might overlap with "boy" or "girl," but either way Frisk is still nonbinary.

TL;DR 2: You can headcanon certain aspects of Frisk's gender identity, but you can't un-canon the fact that Frisk is a they, not a she or a he.